Edge triggered is like a revolver trigger . When the trigger of revolver is pulled a bullet is fired . So even if the trigger is not released from pulled position no bullets are fired . Edge triggered is concerned only from the signal going 0 to 1 or vice versa.
Now think of a machine gun . Once I pull the trigger , bullets would be fired till it comes to its original position .. this refers to level triggered
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A better example is a smartphone keypad and a keyboard .
In a keypad if you press a key it would still display a single character no matter how many seconds you press it for . ( for e.g. if I press 6 for 5 seconds smartphone would still display 6 once ). This is edge triggered . We perform a particular action only if signal changes from 0 t0 1 or 1 to 0 . For e.g. if a signal is active high and edge triggered action would be performed only when it goes from 0 to 1
But in a keyboard if you press a key it would give a string of that character or number till you don't stop pressing the key. ( for e.g. 666666....) this is level triggered . We perform the particular action till the signal is available . That is if a signal is active high task will be performed till its active high . That is only when it is 1 .
